Retinopathy of prematurity (ROP) is an eye disorder caused by abnormal blood vessel growth in the light sensitive part of the eyes (retina) of premature infants.

ROP generally affects infants born before week 31 of pregnancy and weighing 2.75 pounds (about 1,250 grams) or less at birth. In most cases, ROP resolves without treatment, causing no damage. Advanced ROP, however, can cause permanent vision problems or blindness.

In ROP, blood vessels swell and overgrow in the light-sensitive layer of nerves in the retina at the back of the eye. When the condition is advanced, the abnormal retinal vessels extend into the jellylike substance (vitreous) that fills the center of the eye. Bleeding from these vessels may scar the retina and stress its attachment to the back of the eye, causing partial or complete retinal detachment and potential blindness.

Treatments

How ROP is treated depends on its severity. Some of the treatments have side effects of their own. Newer research has shown promise in treating advanced cases of ROP with a combination of traditional therapy and drugs.

• Laser therapy. The standard treatment for advanced ROP, laser therapy burns away the area around the edge of the retina, which has no normal blood vessels. This procedure typically saves sight in the main part of the visual field, but at the cost of side (peripheral) vision. Laser surgery also requires general anesthesia, which may be risky for preterm infants.
• Cryotherapy. This was the first treatment for ROP. Cryotherapy uses an instrument to freeze a specific part of the eye that extends beyond the edges of the retina. It is used rarely now because outcomes from laser therapy are generally better. As with laser therapy, the treatment destroys some peripheral vision and must be done under general anesthesia.

• Medications. Research on anti-vascular endothelial growth factor (anti-VEGF) drugs to treat ROP is ongoing. Anti-VEGF drugs work by blocking the overgrowth of blood vessels in the retina. The medication is injected into the eye while the infant is under a brief general anesthesia. Although no drugs have received Food and Drug Administration (FDA) approval to treat ROP specifically, some medications approved for other uses are being explored as alternatives to laser therapy, or to be used in conjunction with it.

  Bevacizumab (Avastin) has FDA approval for treating colon cancer, but is also widely used to curb the overgrowth of retinal blood vessels in two serious adult eye diseases, wet macular degeneration and advanced diabetic retinopathy. The drug has shown some promise in treating ROP in initial research and may be an option for preterm infants at highest risk of vision loss. Other FDA-approved drugs for eye injections, such as ranibizumab (Lucentis), aflibercept (Eylea) and pegaptanib (Macugen), also are being used and studied as ROP treatments.

Combination treatment

Studies have shown that anti-VEGF drugs may improve outcomes when used in conjunction with laser therapy.

More research is needed into the timing of anti-VEGF drugs for a preterm infant, the optimal dose of the medication and how long its effects last. Doctors don't yet know the long-term impact of using these drugs in preterm infants. Some concern exists that the drugs might slow down the formation of normal blood vessels in other parts of a baby's body.